A long thread and I lost track somewhat, but, yes, from KTSAN (datarace detector) point of view we will need a way to understand whenthings are ordered due to data and control dependencies(i.e.effectively acquire but only wrt the dependent stuff).There is a logic level and physical level, it's perfectly fine if onphysical level all these _DEP/_CTRL variants are no-op (the same asREAD_ONCE, at least on todays archs with todays compilers). But onlogical level they represent a well defined, meaningful thing. Say,when you proof-read code for correctness, the fact that there is adependency can be important and crucial. But tools can's always figurethat out, and even if they can it's still useful to distinguishbetween normal dependencies (that are all over the place) and the onesthat are important for correctness. It also makes code more explicit,rather then relying on some tricky implicit guarantees. Say, like__user annotations which we could wipe out from codegen point of view.